In the 10 years since the brand extension in WWE, the opinions of the diehard fan of the product have really shifted because of this move.
Initially, the brand extension was awesome. It made WWE feel like it was two companies in one, as the RAW and Smackdown brands had superstars that were exclusive to a specific show. Championships stayed exclusive for the most part, except for the WWE Championship, which would have the champion initially bounce back and forth between shows. When the World Heavyweight Championship was included, world titles became exclusive to respective brands. Eventually, superstars would change brands without real reasons to explain why.
Nowadays, RAW features talent from Smackdown to promote the Friday night show, while Smackdown has seen RAW superstars appear to try and boost ratings. There doesn't seem to be any order to things anymore, as a RAW superstar can go after a title featured on Smackdown with little that can be said against it. Gone are the days where a brand being left without a world title was a compelling storyline. This leads fans to wonder why the brands aren't combined right now.
There's one reason to keep two separate brands still going in WWE. That simple reason is for the touring schedules.
The schedules may get complicated for some superstars, but most of the roster that goes out on tour gets to stick to a precise schedule, which will include at least one event per week that will be televised to the masses. What happens at a live event may not matter to storylines and not every competitor seen will have even existed at the time in the grand scheme of things for WWE, but it is those shows that help to satisfy so many markets every single year.
Not every city gets to host a WrestleMania or even an episode of RAW.
To satisfy as many areas as possible, the roster is just about split in half. Advertising for a RAW house show means that you'll get the feel of a RAW episode with superstars you would normally see every week on television when watching RAW. Storylines may fall to the back burner at a house show, but it helps to continue that spark in interest for the product to the fans.
Having these two brands helps to make more stars. With just one main-event scene, the same few guys would be getting the chances with little end in sight. As there are two brands, the chances for a young up-and-comer to move up the ranks theoretically gets doubled. How long would it have taken Sheamus to get into the World Heavyweight Championship discussion, let alone hold the strap for six months? The house shows give superstars an intimate setting for fans to grow with a superstar and latch on to them as they climb the ladder.
More opportunities also lessens the work load for many superstars. John Cena and CM Punk do not need to appear on television twice a week, not to mention shows like Main Event, Superstars and NXT, which also feature main roster members. Keeping a superstar exclusive to one brand, for the most part, helps to not overwork them. For instance, Smackdown was in Egypt this week for three dates in the African country. Because of the split brands, it was simple to put some superstars in that tour over others.
The split brands also has helped to elevate countless stars. Even though Sheamus was a two-time WWE Champion while on RAW, would he be as revered as he is today without his journey to Smackdown and long reign as World Heavyweight Champion?
Without two brands, there wouldn't be two world champions, as well as both the Intercontinental and United States Championships. Would guys like Zack Ryder or Antonio Cesaro even become champions at the times that they did?
Now that Smackdown is featured prominently on RAW, it doesn't seem like the second brand and titles for a second show are very necessary. If for nothing else, however, it makes the scheduling for house shows, as well as televised programming, even easier. That was the reason that brands were split a decade earlier following the absorption of WCW and their superstars. Now, the need for the two separate brands feels a bit less necessary.
Personally speaking, the brands should remain separated, but WWE would be better suited to have a look a lot like when the brand extension was done in the first place. Superstars were exclusive to one show, brand rivalry was commonplace, while only champions were allowed on both programs.
It sure would spice up Superstars, where you could see RAW superstars face Smackdown superstars or even use that as the premise for Main Event. Eventually, it could be possible that the brands could combine back together. For now, keeping them separate is easier for superstars and is the smarter financial move.